The journal of Dermatology Vol. 19: 201-207. 1992

Original articles

The Ultrastructural Histopathology of Eosinophilic Pustular Folliculitis Yuji Horiguchi, Tsuneo Mitani* and Shigeo Ofuji* Abstract The follicular skin lesions of a patient with eosinophilic pustular folliculitis were investigated by electron microscopy. Pustules in the outer root sheath contained acantholytic keratinocytes with numerous microvilli and features of desmosomal cleavage. The infiltrating eosinophils and neutrophils exhibited autolytic or degenerative changes rather than degranulation. The aggregated tubule-vesicular structures were associated with the debris of autolytic eosinophils. Multiple, tiny, bubble-like structures enclosed within a membrane were frequently seen in the intercellular space. The intercellular space of the outer root sheath was widened with decreased desmosomal adhesion between the keratinocytes, but no intracellular edema was detectable. The infiltrating lymphocytes, predominantly T-cells with convoluted nuclei, extended cytoplasmic processes to adjacent keratinocytes. Apposition of T-Iymphoeytes and Langerhans cells was noted. Some keratinoeytes in the outer root sheath contained large, sebaceous lipid droplets. No obvious virus particles or other pathogenic agents were detected. It is possible that T-Iymphocytes and other immunosurveillance cells are involved in the pathomechanism of eosinophilic pustular folliculitis.

Key words: eosinophilic pustular folliculitis; eosinophil; electron microscopy

Introduction The histopathology of follicular lesions in the early stages of eosinophilic pustular folliculitis has been described as spongiosis or small vesiculation of the outer root sheath with infiltration of eosinophils and neutrophils accompanied by a small number of mononuclear cells, due to degeneration and disintegration of the epithelial cells. In advanced stages, vesicles are seen longitudinally in the outer root sheath, extending from the subcorneal osteum to the level of the entry of the sebaceous gland, occasionally reaching the gland itself (1). Many hypotheses have been proposed which describe how the eosinophils and other inflamReceived November 8, 1991; accepted for publication january 28,1992. Department ofDermatology, Faculty of Medicine, Kyoto University, Kyoto, and *Kansai-Denryoku Hospital, Osaka, Japan. Reprint requests to: Yuji Horiguchi, M.D., Department of Dermatology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606,japan.

matory cells primarily infiltrate hair follicles in this skin disease (2-5), but not pathogenic agents have been detected or identified from the lesions or blood of patients, and no acceptable pathomechanism has yet been established. Recently, we encountered a patient with follicular lesions of eosinophilic pustular folliculitis and examined an early lesion with routine transmission electron microscopy in an attempt to determine the pathomechanism.

Report of a Case Materials and Methods A 28-year-old Japanese female without any particular past medical or family history noticed pruritic, erythematous eruptions on her face in February of 1988, followed by papuloerythematous eruptions on the back. She was treated with oral indomethacin tablets (75-100 mg/day) with symptomatic improvement She discontinued the indomethacin after several weeks and the eruptions promptly reappeared. She then restarted the treatment, but the skin lesions lingered and intermit-

202

Horiguchi et al

Fig. 1. Tiny papules with red halo were cropped on the left shoulder. The biopsy sample was obtained from the pointed area. tantly enlarged. Physical examination revealed a coin-like erythematous plaque on the face and fairly well defined, 3-5 ern diameter areas of crops of follicular papules with slightly infiltrated red halos on the back, left shoulder and thighs. Some papules had pustules or tiny crusts. The percentage of eosinophils in the peripheral leukocytes was 5-10% during the course. A punch-biopsy sample from the back containing a papule with a red halo, but no macroscopical pustules (Fig. 1), was cut into small pieces, fixed with phosphate-buffered 2.5% glutaraldehyde solution for 4 hours, washed with phosphate buffer overnight, and post-fixed with phosphate-buffered 1% osmium tetroxide. The sample pieces were then dehydrated with an ethanol series and propylene oxide and embedded in Epon. The blocks, containing tangentially cross-sectioned follicles, were adequately trimmed and underwent further ultrathinsectioning. The ultrathin sections were collected on fine bar-hexagonal mesh grids (No 200) without a supporting membrane, stained with uranyl acetate and Reynolds' lead citrate, and examined under an H300 electron microscope.

Results Three follicles examined by both light and electron microscopy exhibited similar changes. Light microscopically, the tangentially sectioned follicle had a longitudinal vesicle in the outer root sheath at the level of the infundibulum. Diffuse edematous and spongiotic changes were observed in the entrance of the

Fig. 2. A low-powered electron micrograph of the obliquely sectioned upper portion of a hair follicle. The intercellular space of the outer root sheath and part of the sebaceous gland (below the arrowheads) is enlarged with infiltrating cells. A longitudinal pustule (asterisk) is present in the upper part of the infundibulum. The numbers denote the areas enlarged in the following figures. Bar= I00 usn.

sebaceous gland and around the vesicle. Inflammatory cells infiltrated the follicle and the surrounding dermis, as well as the vesicle. The hair remained in the follicle, but the inner root sheath had partly disappeared. Electron microscopy examined the lower portion of the infundibulum including the vesicle and sur-

Ultrastructural Histopathology of Eosinophilic Pustular Folliculitis

203

Fig. 3. A: A magnified photograph of area 1 in Figure 2. Acantholytic keratinocytes in the pustule exhibit surface microvilli-like projections (arrows) and aggregated tonofibrils (Tf) surround the nucleus. Bar=10 pm. B: A magnified photograph of area 2 in Figure 2 shows and acantholytic cell with remaining attachment plaques of desmosomes (arrows) with connecting tonofibrils. Bar=10 tuu.

rounding dermal connective tissue (Fig. 2). Many acantholytic keratinocytes were seen within the vesicle. Most of the acantholytic cells exhibited surface microvilli and coarsely aggregated tonofibrils around the nuclei. Some acantholytic keratinocytes retained desmosomal attachment plaques with connecting tonofibrils on their cell surface. The mitochondria of some keratinocytes were edematous, but no intracellular edema was seen. There were only a few keratinocytes exhibiting degeneration (Fig. 3). Some of the infiltrating eosinophils and neutrophils seemed intact, while others showed degenerative changes with loss of their nuclear membrane and rupture of the cytoplasmic membrane. Structures containing aggregated tubules and 60-80 nm diameter vesicles were associated with the debris of eosinophils. Obvious degranulating figures were rarely detected (Fig. 4). Although intracytoplasmic edema was not seen, the intercellular space of the outer root sheath surrounding the vesicle was enlarged with decreased desmosomal adhesion. Cell debris, containing multiple vesicles 60-80 nm in diameter, which should be called "micro-

bubbles", was enclosed by a membrane and was frequently seen in the enlarged intercellular space (Fig. 5). The inflammatory infiltrates in the vesicle and edematous outer root sheath consisted of eosinophils, neutrophils, lymphocytes, macrophages, and Langerhans cells. Most of the lymphocytes were morphologically T-lymphocytes with convoluted nuclei. They extended cytoplasmic projections to the cell surface of adjacent keratinocytes (Fig. 6). Apposition of Langerhans cells and T-lymphocytes was occasionally detected. The number of Birbeck granules in the Langerhans cells was decreased (Fig. 7). Some acantholytic keratinocytes located proximally to the entrance of the sebaceous gland contained large, sebaceous lipid droplets with amorphous, dark and light, inner structures in the cytoplasm (Fig. 8). There were no particular particles or structures indicative of virus or exogenous agents. Discussion The acantholytic keratinocytes in the pustules looked like those seen in the blisters of pemphigus, exhibiting many microvilli projec-

204

Horiguchi et al

Fig. 4. A: A magnified photograph of area 3 in Figure 2 shows an eosinophil (Eo), a neutrophil (Neu) and an autolytic neutrophil (Au). The eosinophil looks intact and contains well developed specific granules with definite crystalloid cores, while the neutrophil contains vacuoles and a small number of granules indicating degranulation. Bar=IO uiu. B: In area 4 of Figure 2, two intact neutrophils (Neu) and part of an autolytic eosinophil (Au) are seen. Bar=lO tun. C: The No.5 arrow of Figure 2 indicates the cellular debris including specific granules of the eosinophil (arrows) and aggregated tubulo-vesicular structures (arrowheads). Bar=lO pm. tions and aggregated tonofibrils in the perinuclear region. The desmosomal attachment plaques with connecting tonofibrils remaining on some acantholytic keratinocytes indicated the preceding cleavage of the desmosomes. The intercellular space of the epithelium around the vesicle was remarkably enlarged

with decreased hemidesmosomal adhesion, and the epithelium appeared spongiotic. However, no intracellular edema, characteristic of spongiosis due to allergic contact dermatitis (6), was seen in the follicles. It is hard to definitively conclude whether the vesicle is formed in the follicles because of cleavage of the desmo-

Ultrastructural Histopathology of Eosinophilic Pustular Folliculitis

205

Fig. 5. A: A magnified photograph of area 6 in Figure 2. A large amount of cytoplasmic debris (arrows and rectangles) is scattered in the enlarged intercellular space. Bar=lO utu. B,C: Magnified photographs ofthe left and right rectangular areas of A Some of the cellular debris consists of an aggregation of multiple tiny vesicles of 60-80 nm in diameter (arrows) enclosed within a membrane (open arrows). Bars=l um.

Fig. 6. A magnified photograph of area 7 in Figure 2. Most of the infiltrating lymphocytes (Ly) are morphologically T-Iymphocytes with convoluted nuclei (asterisk). They extend the cytoplasmic processes (arrows) to the cell surface of adjacent keratinocytes. Bar=lO p.m.

somes or intercellular edema, but as Holst (7) suspected, proteolytic enzymes released from disintegrated leukocytes seem to damage the intercellular adhesions of the follicular epithelium in eosinophilic pustular folliculitis, modifying pustule formation. The intact eosinophils observed in the pustules, as well as those infiltrating or surrounding the follicles, contained specific eosinophilic granules with defined crystalloid cores. Features suggesting activation of the eosinophils, such as vacuolization, decreased granule density, and disappearance of the crystalloid cores (8) were rarely detected in the infiltrates. Thus, the eosinophils infiltrating the follicles of eosinophilic pustular folliculitis seem quite different from the "activated eosinophils" (8) seen in the infiltrates ofbullous pemphigoid or other skin diseases accompanied by infiltration of activated eosinophils. Although a few completely degranulated leukocytes were seen in the follicle, the morphological features of the infiltrating eosinophils and neutrophils of this disease are primarily degeneration and autolysis, rather than degranulation and activation. Some of the cellular debris of the eosinophils

206

Horiguchi et al

Fig. 7. A: The No.8 arrow in Figure 2 indicates apposition of a Langerhans cell (LC) and aT-lymphocyte (Ly). The lymphocyte extends cytoplasmic processes to the Langerhans cell (arrow). The adjacent cell (asterisk) without Birbeck granules seems to be a macrophage. Bar=IO /-lm. B: A magnified photograph of the rectangular area of A shows only a few Birbeck granules (arrows) in the cytoplasm. Bar=l utn.

contained a tubulo-vesicular structure with specific granules. Multiple vesicles enclosed within a membrane, looking like "microbubbles", were frequently seen in the intercellular space of the outer root sheath. These tubulo-vesicular and microbubble structures, which have not been described in the previous literature, seemed to originate from, or be related to, the autolytic eosinophils. The infiltrating lymphocytes were predominantly T-cells with convoluted nuclei as determined by electron microscopy. They extended cytoplasmic processes to the cell surface of the keratinocytes. They also were apposed with Langerhans cells containing few Birbeck granules. The significance of these findings is

Fig. 8. The No.9 arrow in Figure 2 indicates an acantholytic cell containing a large, sebaceous lipid droplet (asterisk) in the cytoplasm. Bar=lO/-lm.

unknown. Several cases of eosinophilic pustular folliculitis have recently been reported in association with human immunodeficiency virus (HIV) infection (9-12). The fact that eosinophilic pustular folliculitis accompanies HIV infection may disclose its pathomechanism, but the relationship between this skin disease and HIV infection remains unclear. There were no findings in this study suggesting exogenous agents, including virus particles, involved in the follicular eruption. The convoluted nuclei of the T-Iymphocytes infiltrating the follicle may suggest the aberrant function of T-Iymphocytes in the pathomechanism of this disease. The large lipid droplets contained in some acantholytic keratinocytes seen in the outer root sheath near the entrance of the sebaceous gland were not homogeneous, but had amorphous, dark and light, inner structure, which strongly suggest that these lipid droplets were those of the sebaceous gland. The reason of an unusual distribution of such keratinocytes is unclear. Possibly, the affected entrance of the sebaceous gland discharged lipid droplets in

Ultrastructural Histopathology of Eosinophilic Pustular Folliculitis

the intercellular space of the outer root sheath, and the acantholytic keratinocytes phagocytosed them. References

7)

8)

1) Ofuji S, Ogino A, Horio T, Ohseko T, Uehara M:

2)

3)

4)

5)

6)

Eosinophilic pustular folliculitis, Acta Derm Venereol (Stockh), 50: 195-203,1970. Cutler TP: Eosinophilic pustular folliculitis, Clin Exp Dermatol, 6: 327-332, 1981. Takematsu H, Nakamura K, Igarashi M, Tagami H: Eosinophilic pustular folliculitis: report of two cases with a review of the Japanese literature, Arch Dermatol, 121: 917-920, 1985. Kuo T-T, Chen S-Y, Chan H-L: Tinea infection histologically simulating eosinophilic pustular folIiculitis,]CutanPathol, 13: 118-122, 1986. Andreano JM, Kantor GR, Bergfeld WF, Tuthill RJ, Taylor JS: Eosinophilic cellulitis and eosinophilic pustular folliculitis,] Am Acad Dermatol, 20: 934-936, 1989. Komura J, Ofuji S: Ultrastructural studies of allergic

9)

10)

11)

12)

207

contact dermatitis in man: epidermal cell changes at 3, 6, and 12 h after application of DNCB, Arch Dermatol Res, 267: 275-282, 1980. Holst R: Eosinophilic pustular folliculitis: report of a European case, Brit] Dermatol, 95: 661-664, 1976. Kay AB: Eosinophils as effector cells in immunity and hypersensitivity disorders, Clin Exp Immunol, 62: 1-12,1985. Soeprono FF, Schinella RA: Eosinophilic pustular folliculitis in patients with acquired immunodeficiency syndrome,] Am Acad Dermatol, 14: 1020-1022, 1986. Jenkins Jr D, Fisher BK, Chalvardjian A, Adam P: Eosinophilic pustular folliculitis in a patient with AIDS, Int] Dermatol, 27: 34-35, 1988. Frentz G, Niordson A-M, Thomsen K.: Eosinophilic pustular dermatosis: an early marker of infection with human immunodeficiency virus?, Brit] Dermatol, 121: 271-274, 1989. Cockerell CJ: Cutaneous manifestations of HIV infection other than Kaposi's sarcoma: clinical and histologic aspects,] Am AcadDermatol, 22: 1260-1269, 1990.

The ultrastructural histopathology of eosinophilic pustular folliculitis.

The follicular skin lesions of a patient with eosinophilic pustular folliculitis were investigated by electron microscopy. Pustules in the outer root ...
811KB Sizes 0 Downloads 0 Views